Some users of Standard 62.1 believe the ventilation-rate procedure (VRP) is “too complicated,” Standard 62.1 chair Roger Hedrick explained. “While the 62.1 committee disagrees with this in most cases—the basics of the VRP are quite straightforward—the committee agrees that application of the multiple-zone-recirculating-system equations described in Section 6.2.5 and Appendix A can be complex.”

Hedrick added: "Difficulty determining an appropriate value for Vpz seems to be a frequent issue with users of the multiple-space equations. The committee decided that supplying a default value would simplify application. However, the default value is necessarily conservative. In a large number of applications, determining the 'lowest zone-primary-airflow value expected at the design condition analyzed' will result in a value for Vpz that is higher than the default, resulting in a reduced outdoor-air-intake requirement."

According to ASHRAE, both the “sports arena (play area)” and “gym, stadium (play area)” space types have ventilation rates based on floor area only, with a per-person rate of zero. Users of the standard have expressed interest in applying demand-controlled ventilation to those space types, which effectively is prohibited by the lack of a per-person component to the ventilation rates.

• Addendum g, which, for space types not listed in Table 6-1, directs users to select the space type most similar to the space in question from Table 6-1 or Table 6-4 and to design the ventilation for the space according to Section 6.2 or Section 6.5, as appropriate.

Currently, users are directed to select the space type from Table 6-1 most similar to the one being designed. However, some space types are ventilated using the exhaust ventilation requirements of Section 6.5 and Table 6-4.

Proposed addenda f and h will be open for public review until Oct. 16, while proposed Addendum g will be open for public review until Oct. 31. For more information, click here.